In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related "sister cell type" to hair cells. We previously identified only one transcription factor gene, Neurod4, as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula). The other 16 transcription factor genes we previously validated in paddlefish were expressed in both ampullary organs and neuromasts. Here, we used our published lateral line organ-enriched gene-set (arising from differential bulk RNA-seq in late-larval paddlefish), together with a candidate gene approach, to identify 25 transcription factor genes expressed in the developing lateral line system of a more experimentally tractable chondrostean, the sterlet (Acipenser ruthenus, a small sturgeon), and/or that of paddlefish. Thirteen are expressed in both ampullary organs and neuromasts, consistent with conservation of molecular mechanisms. Seven are electrosensory-restricted on the head (Irx5, Irx3, Insm1, Sp5, Satb2, Mafa and Rorc), and five are the first-reported mechanosensory-restricted transcription factor genes (Foxg1, Sox8, Isl1, Hmx2 and Rorb). However, as previously reported, Sox8 is expressed in ampullary organs as well as neuromasts in a catshark (Scyliorhinus canicula), suggesting the existence of lineage-specific differences between cartilaginous and ray-finned fishes. Overall, our results support the hypothesis that ampullary organs and neuromasts develop via largely conserved transcriptional mechanisms, and identify multiple transcription factors potentially involved in the formation of electrosensory versus mechanosensory lateral line organs.

• Klíčová slova
• ampullary organ, electrosensory, lateral line organs, mechanosensory, neuromast, paddlefish, sterlet, sturgeon,
• Publikační typ
• časopisecké články MeSH

Nanoparticles are finding increasing applications in diagnostics, imaging and therapeutics in medicine. Iron oxide nanoparticles (IONs) have received significant interest of scientific community due to their distinctive properties. For the first time, we have delivered IONs into germ cells in any species. Our results showed that sturgeon primordial germ cells (PGCs) delivered with IONs could be detected until seven days post fertilization (dpf) under fluorescent microscope and at 22 dpf by micro-CT. Delivery of IONs into cells could be helpful for studying germ cell biology and the improvement of germ cell-based bio-technologies as isolation of PGCs using magnetic activated cell sorting or application of hyperthermia for a host sterilization purpose. Intriguingly, in our study, we did not find any toxic effects of IONs on the survival and hatching rates of sturgeon embryos when compared with embryos injected with FITC-dextran only.

• Klíčová slova
• Acipenser, caviar, hyperthermia, iron oxide nanoparticles, micro-CT, sterilization,
• MeSH
• nanočástice * MeSH
• ovum metabolismus   MeSH
• rentgenová mikrotomografie MeSH
• ryby metabolismus   MeSH
• spermie metabolismus   MeSH
• železité sloučeniny chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ferric oxide MeSH Prohlížeč
• železité sloučeniny MeSH

Sturgeons also known as living fossils are facing threats to their survival due to overfishing and interference in natural habitats. Sterlet (Acipenser ruthenus) due to its rapid reproductive cycle and small body size can be used as a sterile host for surrogate production for late maturing and large sturgeon species. Dead end protein (dnd1) is essential for migration of Primordial Germ Cells (PGCs), the origin of all germ cells in developing embryos. Knockout or knockdown of dnd1 can be done in order to mismigrate PGCs. Previously we have used MO and UV for the aforementioned purpose, and in our present study we have used CRISPR/Cas9 technology to knockout dnd1. No or a smaller number of PGCs were detected in crispants, and we also observed malformations in some CRISPR/Cas9 injected embryos. Furthermore, we compared three established methods to achieve sterility in sterlet, and we found higher embryo survival and hatching rates in CRISPR/Cas9, UV and MO, respectively.

• Klíčová slova
• Acipenser, PGCs, caviar, conservation, genome editing, morpholino oligonucleotide,
• Publikační typ
• časopisecké články MeSH

Most of sturgeon species (Acipenseridae) are currently critically endangered. Attempts to revive these populations include artificial breeding in hatcheries. However, under artificial reproduction, sturgeon embryos occasionally develop atypically, showing 3, 5, 6, 7, 9, or 10 cells at the 2- to 4-cell stage. This study was undertaken with the objective of understanding the mechanism of the atypical division (AD) in embryos during artificial breeding. Using several sturgeon species, we tested two hypotheses: (1) polyspermy and (2) retention of the second polar body. We found that (1) AD embryos survive similar to controls, (2) the ratio of AD embryos is positively correlated with the amount of sperm used for fertilization, (3) the number of micropyles and the area covered by them in AD embryos is significantly greater when compared to controls, (4) numerous spermatozoa nuclei are in the cytoplasm after fertilization, (5) all AD embryos are mosaics, and (6) AD fishes with n/2n ploidy contain diploid cells from maternal and paternal genetic markers, while the haploid cells contained only paternal ones. These results clearly indicate that AD embryos arise from plasmogamy where the accessory spermatozoon/spermatozoa entry the egg and develop jointly with zygotic cells. This suggests that a well-controlled fertilization procedure is needed to prevent the production of sturgeon with irregular ploidy, which can have detrimental genetic effects on sturgeon populations. On the other hand, if AD fish can produce haploid-derived clonal gametes, induction of multiple-sperm mosaicism might be a useful tool for the rapid production of isogenic strains of sturgeons.

• MeSH
• asistovaná reprodukce veterinární   MeSH
• chov MeSH
• diploidie MeSH
• embryonální vývoj genetika   MeSH
• fertilizace genetika   MeSH
• haploidie MeSH
• modely genetické MeSH
• mozaicismus * MeSH
• ohrožené druhy MeSH
• ryby embryologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A technique for rescuing and propagating endangered species involves implanting germ line stem cells into surrogates of a host species whose primordial germ cells (PGCs) have been destroyed. We induced sterilization in sterlet (Acipenser ruthenus) embryos by means of ultraviolet (UV) irradiation at the vegetal pole, the source of early-stage PGCs of sturgeon eggs. The optimal cell stage and length of UV irradiation for the effective repression of the developing PGCs were determined by exposing embryos at the one- to four-cell stage to different doses of irradiation at a wavelength of 254 nm (the optimal absorbance spectrum for germplasm destruction). The vegetal pole region of the embryos was labeled immediately upon irradiation with GFP bucky ball mRNA to monitor the amount of germ plasm and FITC-dextran (M.W. 500,000) to obtain the number of PGCs in the embryos. The size of the germ plasm and number of surrounding mitochondria in the irradiated embryos and controls were observed using transmission electron microscopy, which revealed a drastic reduction in both on the surface of the vegetal pole in the treated embryos. Furthermore, the reduction in the number of PGCs was proportional to the dose of UV irradiation. Under the conditions tested, optimum irradiation for PGCs removal was seen at 360 mJ/cm2 at the one-cell stage. Although some PGCs were observed after the UV irradiation, they significantly reduced in number as the embryos grew. We conclude that UV irradiation is a useful and efficient technique to induce sterility in surrogate sturgeons.

• MeSH
• embryo nesavčí účinky záření   MeSH
• embryonální zárodečné buňky účinky záření   transplantace   MeSH
• ohrožené druhy * MeSH
• ryby embryologie   MeSH
• sterilizace reprodukční metody   veterinární   MeSH
• ultrafialové záření * MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Sturgeons (Acipenseriformes) are among the most endangered species in the world due to fragmentation and destruction of their natural habitats and to overexploitation, mainly for highly priced caviar. This has led to the development of sturgeon culture, originally for reintroduction, but more recently for caviar production. In both cases, accurate species identification is essential. We report a new tool for accurate identification of Huso huso and Acipenser ruthenus based on nuclear DNA markers. We employed ddRAD sequencing to identify species-specific nucleotide variants, which served as specific binding sites for diagnostic primers. The primers allowed identification of Huso huso and Acipenser ruthenus as well as their discrimination from A. baerii, A. schrenckii, A. gueldenstaedtii, A. stellatus, A. persicus, A. mikadoi, A. transmontanus, and H. dauricus and identification of A. ruthenus and H. huso hybrids with these species, except hybrid between A. ruthenus and A. stellatus. The species-specific primers also allowed identification of bester (H. huso × A. ruthenus), the most commercially exploited sturgeon hybrid. The tool, based on simple PCR and gel electrophoresis, is rapid, inexpensive, and reproducible. It will contribute to conservation of remaining wild populations of A. ruthenus and H. huso, as well as to traceability of their products.

• MeSH
• buněčné jádro genetika   MeSH
• DNA genetika   MeSH
• druhová specificita MeSH
• genetické markery MeSH
• hybridizace genetická * MeSH
• ryby genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• genetické markery MeSH